As is known, warehouses are particularly large and spacious prefabricated buildings that are usually designed to accommodate machinery for industrial or craft processing, or are used to temporarily store materials, goods or vehicles of various type, and which substantially consist of a large flat roof which rests in horizontal position on a series of vertical pillars usually made of reinforced-concrete.
In case of prefabricated reinforced-concrete warehouses, the horizontal roof is formed by a series of long horizontal reinforced-concrete lintels usually with L-shaped or overturned T-shaped transversal section, which are arranged parallel and next to each other, in abutment on the upper ends of the pillars; and by a series of horizontal reinforced-concrete covering beams, which are positioned spaced one next to the other, astride of two immediately adjacent lintels, so as to rest on the lintels with the two ends thereof.
Due to this particular modular structure with lintels and covering beams simply resting one on the other, the horizontal roof may be assembled using prefabricated reinforced-concrete lintels and covering beams.
Although it allows the costs for building the warehouse to be greatly contained, the modular structure described above does not provide great resistance to seismic events of undulatory type. In coincidence with this type of seismic events, the covering beams of the roof indeed tend to be displaced forwards and backwards and/or to rotate horizontally on the lintels, until one of the ends of one of the beams crosses/passes over the edge of the lintel and falls on the ground, with all the risks this involves for the people who may be inside the warehouse.
To obviate this drawback, certain manufacturers of prefabricated reinforced-concrete warehouses have decided to anchor the ends of the covering beams in a rigid manner to the various lintels by means of metal material brackets which are structured so as to prevent any related movement between the two components.
Obviously, the rigid connection between covering beams and lintels has made the upper part of the warehouse much more rigid and heavier, thus significantly modifying the dynamic behavior of the structure in response to seismic events, with the problems this involves. In case of seismic events, in fact, a more rigid and heavier roof may expose the reinforced-concrete pillars to much greater mechanical stresses than those projected, with the risks of building collapsing resulting therefrom.